Adenosine deaminase inhibitor

ABSTRACT

The present invention relates to adenosine deaminase inhibitors containing at least one O-alkylated moiety and the pharmaceutically acceptable salts thereof. 
     The pharmaceutical compositions of the present invention include adenosine deaminase inhibitors containing at least one of the compounds represented by Formula (I): ##STR1## wherein each of R 1 , R 2 , and R 3  are the same or different and is hydrogen or alkyl; 
     R is hydrogen, alkyl, alkenyl, alkynyl, hydroxyalkynyl, alkoxy, phenyl, hydroxy, amino, alkylamino, phenylamino or halogen; 
     X is hydrogen, alkyl, alkynyl, allyl, methallyl, cycloalkyl, alkyl having one or more hydroxy groups, phenyl, substituted phenyl, alkyl having one or more phenyl groups, alkyl having one or more substituted phenyl groups, bicycloalkyl, naphthylalkyl, acenaphthylenylalkyl or a compound represented by Formula (II) or Formula (III) ##STR2## wherein Z is hydrogen, hydroxy or lower alkoxy; Q is hydrogen or hydroxy; 
     A is --CH 2  --, --O--, --S-- or a mere linkage; 
     Y is (CH 2 ) n  -- or a mere linkage; 
     n is an integer from 1 to 3; and 
     any of R 1 , R 2 , and R 3  is R 3  lower alkyl.

FIELD OF THE INVENTION

The present invention relates to adenosine deaminase inhibitorscontaining at least one O-alkylated moiety and the pharmaceuticallyacceptable salts thereof.

BACKGROUND OF THE INVENTION

Adenosine deaminase is an enzyme producing inosine by deamination ofadenosine in vivo and is prevalent in animals and microorganisms. Whenadenosine deaminase is inhibited, the adenosine concentration in tissuesis increased while the inosine concentration is decreased whereuponendogenous inactivation of adenosine is inhibited. When the tissue is inan ischemic state, neutrophils produce activated oxygen and adenosineinhibits this oxygen production. In addition, adenosine directlyeliminates the produced activated oxygen. Further, as a result of adecrease in the inosine concentration, the supply of hypoxanthine isdecreased. Hypoxanthine is a substrate in the xanthine-xanthineoxidasesystem. The xanthine-xanthineoxidase system is one of the systemsproducing the activated oxygen. It has been known that adenosinedeaminase inhibitors, which inhibit the production of such activatedoxygen sources and also eliminate them, exhibit pharmacological actionssuch as improvement of coronary and cerebral blood vessel circulation,prevention and therapy of renal diseases, and antiinflammatory activity.

It has been found that the O-alkylated adenosine derivatives of theinstant invention exhibit excellent adenosine deaminase inhibitingaction.

SUMMARY OF THE INVENTION

The present invention pertains to adenosine deaminase inhibitorscontaining at least one O-alkylated moiety and the pharmaceuticallyacceptable salts thereof.

The pharmaceutical compositions of the present invention includeadenosine deaminase inihibitors containing at least one of the compoundsrepresented by Formula (I): ##STR3## wherein each of R₁, R₂, and R₃ arethe same or different and is hydrogen or alkyl;

R is hydrogen, alkyl, alkenyl, alkynyl, hydroxyalkynyl, alkoxy, phenyl,hydroxy, amino, alkylamino, phenylamino or halogen;

X is hydrogen, alkyl, alkynyl, allyl, methallyl, cycloalkyl, alkylhaving one or more hydroxy groups, phenyl, substituted phenyl, alkylhaving one or more phenyl groups, alkyl having one or more substitutedphenyl groups, bicycloalkyl, naphthylalkyl, acenaphthylenylalkyl or acompound represented by Formula (II) or Formula (III) ##STR4## wherein Zis hydrogen, hydroxy or lower alkoxy; Q is hydrogen or hydroxy;

A is --CH₂ --, --O--, --S-- or a single bond forming a five-memberedring;

Y is (CH₂)_(n) -- or a single bond;

n is an integer from 1 to 3; and at least one of R₁, R₂, and R₃ isalkyl, such as a lower alkyl.

The compounds represented by Formula (I) are present in the adenosinedeaminase inhibitors in a pharmaceutically effective amount.

The compounds of the present invention having adenosine deaminaseinhibiting action are useful pharmaceutical compositions for theprevention and therapy of various kinds of diseases. Such diseasesinclude ischemic heart diseases, diseases caused by cerebrovasculardisorder, renal diseases and allergic diseases. Moreover, the compoundsof the present invention are very useful pharmaceutical compositions forthe prevention and therapy of post-operative complicated diseasesbecause they inactivate activated oxygen which is generated in ischemicareas during the recirculation of blood after operations.

The compounds of the instant invention may also be administered beforeor together with aniticancer drugs and/or antiviral drugs.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to adenosine deaminase inhibitorscontaining a pharmaceutically effective amount of at least one of thecompounds represented by the following general formula (I) orpharmaceutically acceptable salts thereof. ##STR5##

In Formula (I) each of R₁, R₂ and R₃ may be the same or different and ishydrogen or alkyl; R is hydrogen, alkyl, alkenyl, alkynyl,hydroxyalkynyl, alkoxy, phenyl, hydroxy, amino, alkylamino, phenylaminoor halogen; X is hydrogen, alkyl, alkynyl, allyl, methallyl, cycloalkyl,alkyl having one or more hydroxy groups, phenyl, substituted phenyl,alkyl having one or more phenyl groups, alkyl having one or moresubstituted phenyl groups, bicycloalkyl, naphthylalkyl,acenaphthylenylalkyl or a group represented by the following generalformulae (II) or (III): ##STR6## Z is hydrogen, hydroxy or lower alkoxy;Q is hydrogen or hydroxy; A is --CH₂ --, --O--, --S-- or a single bondforming a five-membered ring; Y is --(CH₂)n-- or a single bond; n is aninteger from 1 to 3 and at least one of R₁, R₂ and R₃ is an alkyl group.

A substituted phenyl or a substituted phenyl group is defined, for thepurposes of this invention, as including a phenyl which has beensubstituted with one or more halogen, lower alkyl, lower alkoxy and/ortrifluoromethyl substituents. In Formula (II), a broken line symbolizesthe presence of either a double bond or a single bond.

In the above general formula (I), each of R₁, R₂ and R₃ may be the sameor different and is hydrogen or alkyl. Preferably, R₁ is a hydrogen or alinear or branched alkyl having 1 to 10 carbons. Exemplary alkyl groupsinclude methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl,tert-butyl, pentyl, isopentyl, neopentyl, tert-pentyl, hexyl,dimethylbutyl, heptyl, octyl, nonyl and decyl. R₂ and R₃ are hydrogen orlinear or branched alkyl having 1 to 4 carbons. Examples of such alkylgroups include methyl, ethyl, propyl, isopropyl, butyl, isobutyl,sec-butyl and tert-butyl. In a preferred embodiment, R₃ is hydrogen. Atleast one of R₁, R₂ and R₃ must be an alkyl.

R is hydrogen, alkyl, alkenyl, alkynyl, hydroxyalkynyl, alkoxy, phenyl,hydroxy, amino, alkylamino, phenylamino, or halogen. Preferred alkylgroups are linear or branched alkyls having 1 to 20 carbons. Exemplaryalkyl groups include methyl, ethyl, propyl, isopropyl, butyl, isobutyl,sec-butyl, tert-butyl, pentyl, isopentyl, neopentyl, tert-pentyl, hexyl,dimethylbutyl, heptyl, octyl, nonyl, decyl and stearyl.

Preferred alkenyl groups are linear or branched alkenyls having 2 to 4carbons. Exemplary alkenyl groups are ethenyl, 1-propenyl, 2-propenyl,1-butenyl, 2-butenyl and 3-butenyl.

Preferably the alkynyl is a linear or branched alkynyl having 2 to 20carbons. Exemplary alkynyl groups include ethynyl, 1-propynyl,2-propynyl, 1-butynyl, 2-butynyl, 3-butynyl, sec-butynyl, pentynyl,isopentynyl, 2-pentynyl, 3-pentynyl, 4-pentynyl, hexynyl, heptynyl,octynyl, nonynyl, decynyl and stearynyl.

If R is a hydroxyalkynyl, it is preferred that the alkynyl issubstituted with one or more hydroxy groups.

Preferred alkoxy groups include linear or branched alkoxy having 1 to 4carbons. Examples of such groups include methoxy, ethoxy, propoxy,isopropoxy, butoxy, isobutoxy, sec-butoxy, and tert-butoxy.

Preferred alkylamino groups include linear or branched alkylamino groupshaving 1 to 10 carbons. Examples of such groups include methylamino,dimethylamino, ethylamino, diethylamino, methylethylamino, propylamino,isopropylamino, butylamino, isobutylamino, sec-butylamino,tert-butylamino, pentylamino, isopentylamino, neopentylamino,tert-pentylamino, hexylamino, dimethylbutylamino, heptylamino,octylamino, nonylamino and decylamino.

Exemplary halogen groups include fluoro, chloro, bromo, and iodo.

X is hydrogen, alkyl, alkynyl, allyl, methallyl, cycloalkyl, alkylhaving one or more hydroxy groups, phenyl, substituted phenyl, alkylhaving one or more phenyl groups, alkyl having one or more substitutedphenyl groups, bicycloalkyl, naphthylalkyl, acenaphthylenylalkyl or acompound represented by Formula (II) or Formula (III). The substitutedphenyl groups include a phenyl which has been substituted with one ormore halogen, lower alkyl, lower alkoxy and/or trifluoromethylsubstituents.

Preferred alkyl groups are linear or branched alkyls having 1 to 6carbons. Exemplary alkyl groups include methyl, ethyl, propyl,isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl,neopentyl, tert-pentyl, hexyl and dimethylbutyl.

Preferred alkynyl groups are linear or branched alkynyls having 2 to 7carbons. Examples of such groups include ethynyl, 1-propynyl,2-propynyl, 1-butynyl, 2-butynyl, 3-butynyl, sec-butynyl, pentynyl,isopentynyl, 2-pentynyl, 3-pentynyl, 4-pentynyl, hexynyl and heptynyl.

Preferred cycloalkyl groups have 3 to 8 carbons. Examples of such groupsinclude cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl,and cyclooctyl.

Preferred alkyl groups having one or more hydroxy substituents arelinear or branched alkyls having 1 to 4 carbons. Examples of such groupsinclude methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl andtert-butyl substituted with one or two hydroxy groups.

Preferred alkyl groups having one or more phenyl or substituted phenylsubstituents are phenylalkyl or diphenylalkyl in which one or twosubstituted phenyl as defined above is/are bonded to a linear orbranched alkyl having 1 to 3 carbons. Examples of such alkyl groups aremethyl, ethyl, propyl, and isopropyl.

Preferred bicycloalkyl groups are endo- or exo-bicyclo 2,2,1!heptyl.

Preferred naphthylalkyls are those in which the naphthyl group is bondedto an alkyl having 1 to 3 carbons. Examples of such alkyl groups aremethyl, ethyl, propyl and isopropyl.

Preferred acenaphthylenylalkyls are those in which acenaphthylenyl isbonded to an alkyl having 1 to 3 carbons. Examples of such alkyl groupsare methyl, ethyl, propyl and isopropyl. It should be noted that the1,2-dihydro form of an acenaphthylenylalkyl may also be used within thecontext of the instant invention. X may also be a group represented byeither Formula (II) or Formula (III).

In a preferred embodiment, X is either hydrogen or an alkyl having 1 to3 carbons.

In the general formulae (II) and (III), Z is hydrogen, hydroxy or loweralkoxy. Preferably Z is a linear or branched alkoxy having 1 to 3carbons. Exemplary alkoxy groups are methoxy, ethoxy, propoxy andisopropoxy. Q is hydrogen or hydroxy. A is --CH₂ --, --O--, --S-- or asingle bond forming a five-membered ring; Y is --(CH₂)n-- or a singlebond; and n is an integer from 1 to 3. In Formula (II) a broken linesymbolizes the presence of either a single bond or a double bond.

When A is a single bond forming a five-membered ring the followinggroups result: ##STR7##

When Y is a single bond the following groups result: ##STR8##

The adenosine derivatives of the present invention include the followingnovel compounds:

(1) Adenosine derivatives represented by the following general formula(Ia): ##STR9## wherein each of R₁ a, R₂ a and Xa may be the same ordifferent and is hydrogen or alkyl;

Ra is an alkyl having more than 6 carbon atoms, alkenyl, alkynyl,hydroxyalkynyl, alkoxy, phenyl, hydroxy, alkylamino or phenylamino; and

at least one of R₁ a and R₂ a is alkyl.

(2) Adenosine derivatives represented by the following general formula(Ib): ##STR10## wherein each of R₁ b and R₂ b may be the same ordifferent and is alkyl;

Rb and Xb is hydrogen or alkyl; and

at least one of Rb and Xb is an alkyl.

(3) Adenosine derivatives represented by the following general formula(Ic): ##STR11## wherein each of R₁ c, R₂ c and Xc may be the same ordifferent and is hydrogen or an alkyl;

Rc is bromo or iodo; and

at least one of R₁ c and R₂ c is an alkyl.

(4) Adenosine derivatives represented by the following general formula(Id): ##STR12## wherein R₁ d is an alkyl having more than 2 carbons.

Preferred substituents in the said adenosine derivatives represented byformulae (Ia) to (Id) are the same groups indicated in the formula (I).

Examples of the compound which is contained as an effective component inthe adenosine deaminase inhibitor in accordance with the presentinvention are as follows:

(Compound 1) 2'-O-Methyladenosine;

(Compound 2) 3'-O-Methyladenosine;

(Compound 3) 2'-O-Ethyl adenosine;

(Compound 4) 2'-O-n-Butyladenosine;

(Compound 5) 2,2'-O-Dimethyl adenosine;

(Compound 6) 2,3'-O-Dimethyl adenosine;

(Compound 7) 2-Isopropyl-2'-O-methyladenosine;

(Compound 8) 2-Isopropyl-3'-O-methyladsnosine;

(Compound 9) 2-Methoxy-3'-O-methyladsnosine;

(Compound 10) 2-Methyl-2'-O-ethyl adenosine;

(Compound 11) 2-Methyl-2'-O-n-butyl adenosine;

(Compound 12) 5'-O-Methyl adenosine;

(Compound 13) 5'-O-n-Butyl adenosine;

(Compound 14) 2',5'-O-Dimethyladenosine;

(Compound 15) 3',5'-O-Dimethyl adenosine;

(Compound 16) 2,5'-O-Dimethyl adenosine;

(Compound 17) 2-Methyl-5'-O-n-butyladenosine;

(Compound 18) N⁶,2'-O-Dimethiladenosine;

(Compound 19) N⁶ -Ethyl-2'-O-methyladenosine;

(Compound 20) N⁶ -n-Butyl-2'-O-methyladenosine;

(Compound 21) N⁶ -Methyl-2'-O-ethyladenosine;

(Compound 22) N⁶ -Methyl-2'-O-n-butyladenosine;

(Compound 23) N⁶ -Methyl-2'-O-n-hexyladenosine;

(Compound 24) N⁶ -Methyl-2'-O-n-octyladenosine;

(Compound 25) N⁶, 5'-O-Dimethyladenosine;

(Compound 26) N⁶ -n-Butyl-5'-O-methyladenosine;

(Compound 27) 2, N⁶,2'-O-Trimethyladenosine;

(Compound 28) 2, N⁶ -Dimethyl-2'-O-ethyladenosine;

(Compound 29) N⁶ -n-Butyl-2,2'-O-dimethyladenosine;

(Compound 30) N⁶,2'-O-Dimethyl-2-hexyladenosine;

(Compound 31) N⁶,2'-O-Dimethyl-2-decyladenosine;

(Compound 32) N⁶,2'-O-Dimethyl-2-(1-hexyn-1-yl)-adenosine;

(Compound 33) N⁶,2'-O-Dimethyl-2-(1-dodecyn-1-yl)-adenosine;

(Compound 34) 2,N⁶,5'-O-Trimethyladenosine;

(Compound 35) N⁶ -n-Butyl-2,5'-O-dimethyladenosine;

(Compound 36) 2,N⁶,3'-O-Trimethyladenosine;

(Compound 37) 2-Phenyl-2'-O-methyladenosine;

(Compound 38) 2-Phenyl-3'-O-methyladenosine;

(Compound 39) 2-Hydroxy-2'-O-methyladenosine;

(Compound 40) 2-Hydroxy-3'-O-methyladenosine;

(Compound 41) 2-Chloro-2'-O-methyladenosine;

(Compound 42) 2-Chloro-3'-O-methyladeonsine;

(Compound 43) 2-Bromo-2'-O-methyladenosine;

(Compound 44) 2-Bromo-3'-O-methyladeonsine;

(Compound 45) 2-Bromo-N⁶,2'-O-dimethyladenosine;

(Compound 46) 2-Bromo-N⁶,3'-O-dimethyladeonsine;

(Compound 47) 2-Iodo-2'-O-methyladenosine;

(Compound 48) 2-Iodo-3'-O-methyladeonsine;

(Compound 49) 2-Fluoro-2'-O-methyladenosine;

(Compound 50) 2-Amino-2'-O-methyladenosine;

(Compound 51) 2-Amino-3'-O-methyladenosine;

(Compound 52) 2-Pentylamino-2'-O-methyladenosine;

(Compound 53) 2-Phenylamino-2'-O-methyladenosine;

(Compound 54) 2-Phenylamino-3'-O-methyladenosine;

(Compound 55) 2-Phenylamino-N⁶,2'-O-dimethyladenosine;

(Compound 56) 2-Phenylamino-N⁶,3'-O-dimethyladenosine;

(Compound 57) 2-(3-Hydroxy-1-propyn-1-yl)-2'-O-methyladenosine;

(Compound 58) 2-(3-Hydroxy-1-propyn-1-yl)-3'-O-methyladenosine;

(Compound 59) 2',3'-O-Dimethyladenosine;

(Compound 60) N⁶,2',3'-O-Trimethyladenosine;

(Compound 61) N⁶ -Methyl-2',3'-O-diethyladenosine;

(Compound 62) N⁶ -n-Butyl-2',3'-O-dimethyladenosine;

(Compound 63) 2,2',3'-O-Trimethyladenosine;

(Compound 64) 2,N⁶,2',3'-O-Tetramethyladenosine;

(Compound 65) N⁶ -Allyl-2'-O-methyladenosine;

(Compound 66) N⁶ -Methallyl-2'-O-methyladenosine;

(Compound 67) N⁶ -(2,3-Dihydroxypropyl)-2'-O-methyladenosine;

(Compound 68) N⁶ -Cyclopropyl-2'-O-methyladenosine;

(Compound 69) N⁶ -Cyclopentyl-2'-O-methyladenosine;

(Compound 70) N⁶ -Cyclopentyl-2'-O-ethyladenosine;

(Compound 71) N⁶ -Cyclopentyl-2,2'-dimethyladenosine;

(Compound 72) N⁶ -Cyclopentyl-2-bromo-2'-O-methyladenosine;

(Compound 73) N⁶ -Cyclohexyl-2'-O-methyladenosine;

(Compound 74) N⁶ -Cyclohexyl-2,2'-O-dimethyladenosine;

(Compound 75) N⁶ -Cycloheptyl-2'-O-methyladenosine;

(Compound 76) N⁶ P-Methoxyphenyl-2'-O-methyladenosine;

(Compound 77) N⁶ -P-Fluorophenyl-2'-O-methyladenosine;

(Compound 78) N⁶ P-Chlorophenyl-2'-O-methyladenosine;

(Compound 79) N⁶ Benzyl-2'-O-methyladenosine;

(Compound 80) N⁶ -(R)-Phenyl-isopropyl-2'-O-methyladenosine;

(Compound 81) N⁶ -(2,2-Diphenylethyl)-2'-O-methyladenosine;

(Compound 82) N⁶ -(exo-Dicyclo 2,2,1!heptyl)-2'-O-methyl-adenosine;

(Compound 83) N⁶ -(endo-Dicyclo 2,2,1!heptyl)-2'-O-methyladenosine;

(Compound 84) N⁶ -(1-Naphthyl)methyl-2'-O-methyladenosine;

(Compound 85) N⁶ -1-(Acenaphthylenyl)methyl-2'-O-methyladenosine;

(Compound 86) N⁶-(1,2-Dihydro-1-acenaphthylenyl)methyl-2'-O-methyladenosine;

(Compound 87) N⁶ -(2,3-Dihydro-1H-inden-1-yl)-2'-O-methyladenosine;

(Compound 88) N⁶ -(2,3-Dihydro-1H-inden-2-yl)-2'-O-methyladenosine;

(Compound 89) N⁶-(2,3-Dihydro-1H-inden-1-yl)methyl-2'-O-methyladenosine;

(Compound 90) N⁶ -(3H-Inden-1-yl)methyl-2'-O-methyladenosine;

(Compound 91) N⁶-(5-Methoxy-2,3-dihydro-1H-inden-2-yl)-2'-O-methyladenosine;

(Compound 92) N⁶ -(1-Tertrahydronaphtyl)-2'-O-methyladenosine;

(Compound 93) N⁶ -(2-Tertrahydronaphtyl)-2'-O-methyladenosine;

(Compound 94) N⁶ -(3,4-Dihydro-1-naphthyl)methyl-2'-O-methyladenosine;

(Compound 95) N⁶ -(5-Hydroxy-1-tetrahydronaphthyl)-2'-O-methyladenosine;

(Compound 96) N⁶-(1-Hydroxy-1-tetrahydronaphthyl)-methyl-2'-O-methyladenosine;

(Compound 97) N⁶ -(5-Methoxy-1-tetrahydronaphthyl)-2'-O-methyladenosine;

(Compound 98) N⁶ -(6-Methoxy-1-tetrahydronaphthyl)-2'-O-methyladenosine;

(Compound 99) N⁶ -(7-Methoxy-1-tetrahydronaphthyl)-2'-O-methyladenosine;

(Compound 100) N⁶ -(4-Chromanyl)-2'-O-methyladenosine;

(Compound 101) N⁶ -(4-Thiochromanyl)-2'-O-methyladenosine;

(Compound 102) N⁶ -Fluorenyl-2'-O-methyladenosine;

(Compound 103) N⁶ -(9-Fluorenyl)methyl-2'-O-methyladenosine;

(Compound 104) N⁶ -(9-Hydroxy-9-fluorenyl)methyl-2'-O-methyladenosine;and

(Compound 105) N⁶ -(9-Xanthenyl)methyl-2'-O-methyladenosine.

The compounds of the present invention as given above may be prepared bya method disclosed, for example, in U.S. Pat. No. 4,843,066 andcorresponding Japanese Laid Open (Kokai) No. 63/239,294, U.S. Pat. No.4,985,409 and corresponding Japanese Laid Open (Kokai) No. 02/184,696,and Great Britain Patent No. 2,226,027A and corresponding Japanese LaidOpen (Kokai) No. 02/218,689.

For example, the adenosine derivatives of the present invention can beprepared as follows:

(1) Adenosine or adenosine derivatives having a lower alkyl group, anamino group or halogen at the 2-position may be alkylated at the 2'-O-or 3'-O-position by an alkylating agent to give the compounds of thepresent invention. A diazoparaffin, such as diazomethane, diazoethane,diazopropane or diazobutane, can be used as the alkylating agent. Theappropriate solvent which does not inhibit the reaction such as1,2-dimethoxyethane can be preferably used. This O-alkylating reactioncan be carried out as follows: (i) The reaction mixture is reacted forseveral minutes to several hours at room temperature in the presence ofa catalyst such as p-toluenesulfonic acid; (ii) The starting material isdissolved in about 80° C. hot water and the alkylating agent such asdiazoparaffin is added thereto, and the reaction mixture is reacted forseveral hours to a day.

(2) Both 3'-O- and 5'-O-positions of the adenosine derivatives areprotected by tetraisopropyldisiloxane (TIPDS) group to carry outO-alkylation selectively at the 2'-O-position. A6-chloropurine-9-riboside and TIPDSCL₂(1,3-dichloro-1,1,3,3-tetraisopropyldisiloxane dichloride) are stirredfor several hours at room temperature to protect the 3'-O- and5'-O-positions, and then the 2'-O-position of the compound protected byTIPDS can be selectively alkylated by an alkylating agent such as methyliodide, ethyl iodide, propyl iodide or butyl iodide in the presence of acatalyst such as silver oxide. After the 2'-O-alkylation, an aminationor alkylamination at the 6-position can be carried out by reacting withammonia or an alkylamine such as methylamine, ethylamine, propylamine orbutylamine with heating. The protecting group, TIPDS, can be removed bya conventional method to give the compounds of the present invention.

(3) In the similar manner, both 2'-O- and 3'-O-positions of theadenosine derivatives are protected by isopropylidene group to carry outO-alkylation selectively at the 5'-O-position. Namely, a6-chloropurine-9-riboside and 2,2-dimethoxypropane are reacted forseveral hours at room temperature in the presence of a catalyst such asp-toluenesulfonic acid to carry out isopropylidenation. After the5'-O-alkylation, an amination or alkylamination at 6-position can becarried out as mentioned above. The protecting group, isopropylidenegroup, can be removed by a conventional method, for example, treatmentwith formic acid, to give the compounds of the present invention.

The resulting compounds of the present invention can be purified byknown methods such as distillation chromatography and recrystallization.Identification is established through, inter alia, melting point,elemental analysis, IR, NMR, UV, mass spectrum, etc.

Adenosine derivatives of the present invention include thepharmaceutically acceptable salts of the compounds represented by thegeneral formula. Examples of such salts are acid addition salts such assalts of hydrochloric acid, sulfuric acid, nitric acid, hydrobromicacid, phosphoric acid, perchloric acid, thiocyanic acid, boric acid,formic acid, acetic acid, haloacetic acid, propionic acid, glycolicacid, citric acid, tartaric acid, succinic acid, gluconic acid, lacticacid, malonic acid, fumaric acid, anthranilic acid, benzoic acid,cinnamic acid, p-toluenesulfonic acid, naphthalenesulfonic acid andsulfanilic acid and salts with alkali metal (e.g. sodium and potassium),alkali earth metal (e.g. calcium and magnesium) and metal (e.g.aluminum).

Adenosine derivatives of the present invention include metal complexesthereof such as, for example, complexes with zinc, nickel, cobalt,copper and iron.

These salts and metal complexes may be manufactured from free adenosinederivatives of the present invention or may be transformed each other.

When there are stereoisomers for the compounds of the present inventionsuch as cis-trans isomers, optical isomers and conformational isomers,the present invention includes all of them.

The following descriptions serve to illustrative examples forpreparation of the compounds of the present invention:

EXAMPLE 1

10 g of 6-chloro-9-(3,5-O-TIPDS)-β-D-ribofuranosyl-9H-purine wasdissolved in 50 ml of ethyl iodide, and silver oxide was added andstirred with heating. The reaction mixture was applied on silica gelcolumn, washed with benzene and then eluted with ethyl acetate/hexane.The eluate was concentrated to dryness under reduced pressure. Theresidue was dissolved in benzene and a 40% (W/V) aqueous solution ofmonomethylamine was added thereto. After stirring overnight, the benzenelayer was separated, washed with 1N HCl and brine, and a mixture of 1Mtetra-n-butylammonium and tetrahydrofuran was added thereto. Thereaction mixture was stirred for 30 minutes at room temperatureconcentration under reduced pressure, and then purified by silica gelcolumn to give 2.1 g of N⁶ -methyl-2'-O-ethyladenosine (Compound 21).

¹ H-NMR (D₂ O): 1.21(3H,t), 3.19(3H,s), 3.58(1H,m), 3.69(1H,m),3.85(1H,dd), 3.93(1H,dd), 4.32(1H,m), 4.55(1H,dd), 4.63(1H,dd),6.10(1H,dd), 8.25(1H,s), 8.30(1H,s)

In the same manner as mentioned above, the following compounds wereobtained.

N⁶ -Methyl-2'-O-n-butyladenosine (Compound 22)

¹ H-NMR (DMSO-d₆): 0.74(3H,t), 1.17(2H,m), 1.37(2H,m), 2.96(3H,s),3.34(1H,m), 3.55(2H,m), 3.68(1H,m), 3.99(1H,m), 4.29(1H,m), 4.47(1H,m),5.15(1H,d), 5.42(1H,m), 5.99(1H,d), 7.81(1H,s), 8.23(1H,s), 8.37(1H,s)

N⁶ -Methyl-2'-O-n-hexyladenosine (Compound 23)

¹ H-NMR (CDCl₃): 0.86(3H,t), 1.16(8H,m), 1.40(2H,m), 3.21(3H,s),3.34(1H,m), 3.48(1H,m), 3.75(1H,m), 3.97(1H,m), 4.36(1H,m), 4.53(1H,d),4.82(1H,dd), 5.82(1H,d), 5.87(1H,s), 6.87(1H,dd), 7.76(1H,s), 8.37(1H,s)

N⁶ -Methyl-2'-O-n-octyladenosine (Compound 24)

¹ H-NMR (CDCl₃): 0.86(3H,t), 1.16(8H,m), 1.24(2H,m), 1.41(2H,m),3.21(3H,s), 3.33(1H,m), 3.49(1H,m), 3.76(1H,m), 3.97(1H,m), 4.36(1H,m),4.53(1H,d), 4.82(1H ,dd), 5.82(1H,d), 6.02(1H,s), 6.87(1H,dd),7.77(1H,s), 8.37(1H,s)

EXAMPLE 2

5.34 g of adenosine was dissolved in 80 ml of dimethylformamide and 800mg of 60% W/W) sodium hydride in mineral oil was added thereto. Afterstirring for 30 minutes in ice-cold water, 2.84 g of methyl iodide in 10ml of dimethylformamide was added dropwise. The reaction mixture wasstirred under cooling for 2 hours and concentrated to dryness underreduced pressure. The residue was dissolved in water and applied oncation exchange column. The fraction was then eluted with 10% (V/V)aqueous solution of methanol collected, concentrated to dryness, andpurified by silica gel column to give 1.36 g of2',3'-O-dimethyladenosine.

m.p.: 180° C.

¹ H-NMR (DMSO-d₆): 3.32(3H,s), 3.40(3H,s), 3.57(1H,m), 3.70(1H,m),4.09(2H,m), 4.54(1H,dd), 5.47(1H,dd), 6.00(1H,d), 7.35(2H,s,D₂O-Disappearance), 8.14(1H,s), 8.38(1H,s)

EXAMPLE 3

2 g of the compound obtained in Example 2 and 2 ml of methyl iodide weredissolved in dimethylacetoamide, and stirred overnight at roomtemperature. The reaction mixture was concentrated to dryness underreduced pressure and 10 ml of 2N sodium hydroxide solution was addedthereto. The solution was refluxed for one hour with heating. Aftercooling to room temperature, the solution was neutralized with 2N HCland applied on Amberlite XAD-7 column. The column was washed with waterand eluted with 50% (V/V) aqueous solution of methanol. The eluate wasconcentrated to dryness under reduced pressure and recrystallized fromethyl acetate to give 1.8 g of N⁶,2',3'-O-trimethyladenosine (Compound60).

m.p.: 165° C.

¹ H-NMR (DMSO-d₆): 2.96(3H,s), 3.31(3H,s), 3.40(3H,s), 3.57(1H,m),3.70(1H,m), 4.09(2H,m), 4.54(1H,dd), 5.49(1H,dd), 6.01(1H,d), 7.83(1H,s,D₂ O-Disappearance), 8.24(1H,s), 8.38(1H,s)

EXAMPLE 4

14.3 g of 6-chloro-9-β-D-ribofuranosyl-9H-purine and 15 g oftriphenylchlorosilane were dissolved in 500 ml of pyridine and stirredfor one hour at room temperature. Pyridine was distilled away and theresidue was dissolved in benzene. The benzene layer was washed with 1NHCl and brine, and then dried over sodium sulfate anhydride. The solventwas distilled off and the residue was recrystallized from a mixture ofhexane and ethyl acetate to give 21.5 g of6-chloro-9-15-O-triphenylsilyl-β-D-ribofuranosyl)-9H-purine.

5.45 g of the resulting product was dissolved in 50 ml of ethyl iodideand silver oxide was added thereto with heating. The reaction mixturewas applied on silica gel column. The column was washed with benzene andeluted with a mixture of hexane and ethyl acetate. The eluate wasconcentrated to dryness under reduced pressure. The residue wasdissolved in benzene and a 40% (W/V) aqueous solution of monomethylaminewas added thereto. After stirring overnight, the benzene layer wascollected, washed with 1N HCl and brine and purified by silica gelcolumn to give6-amino-9-(5-O-triphenylsilyl-β-D-ribofuranosyl)-9H-purine. Theresulting product was dissolved in tetrahydrofuran andtetra-n-butylammonium floride in tetrahydrofurane was added thereto.After stirring for 30 minutes at room temperature, the solution wasconcentrated to dryness under reduced pressure and purified by silicagel column to give 600 mg of N⁶ -methyl-2',3'-O-diethyladenosine(Compound 61).

m.p.: amorphous

¹ H-NMR (MeOH-d₄): 1.07(3H,t), 1.22(3H,t), 3.08(3H,s), 3.48(1H,m),3.58(1H,m), 3.65(2H,m), 3.70(1H,dd), 3.87(2H,m), 4.20(1H,dd),6.00(1H,d), 8.20(1H,s), 8.23(1H,s)

EXAMPLE 5

2-Methyladenosine was dialkylated in the same manner as Example 2 togive 2,2',3'-O-trimethyladenosine (Compound 63).

m.p.: 156° C.

¹ H-NMR (DMSO-d₆): 2.39(3H,s), 3.28(3H,s), 3.40(3H,s), 3.58(1H,m),3.70(1H,m), 4.08(1H,m), 4.13(1H,m), 4.52(1H,m), 5.80(1H,m,D₂O-Disappearance),5.95(1H,d), 7.27(2H,s,D₂ O-Disappearance), 8.28(1H,s)

EXAMPLE 6

Compound 63 was methylated by methyl iodide and then rearranged to give2,N⁶,2',3'-O-tetramethyladenosine (Compound 64).

¹ H-NMR (DMSO-d₆): 2.43(3H,s), 2.94(3H,s), 3.28(3H,s), 3.40(3H,s),3.57(1H,m), 3.70(1H,m), 4.08(1H,m), 4.13(1H,m), 4.52(1H,m), 5.79(1H,m,D₂O-Disappearance), 5.96(1H,d), 7.71(1H,s,D₂ O-Disappearance), 8.26(1H,s)

EXAMPLE 7

1.2 g of 2-iodoadenosine was suspended in 150 ml of 1 mmol tin chloridedihydrate/methanol. 50 ml of 0.4-0.5M diazomethane in1,2-dimethoxyethane was added with stirring. After stirring for one hourat room temperature, the reaction mixture was concentrated to drynessunder reduced pressure. The resulting product was applied on ODS columnand eluted with 40% (V/V) methanol in 0.1% (V/V) aqueous solution ofTFA. First, 2-iodo-2'-O-methyladenosine (Compound 47) was eluted, andthen 2-iodo-3'-O-methyladenosine (Compound 48) was eluted. Bothfractions were concentrated to dryness to give 135 mg of Compound 47 and56 mg of Compound 48.

2-iodo-2'-O-methyladenosine (Compound 47)

¹ H-NMR (D₂ O): 3.52(3H,s), 3.92(1H,dd), 3.97(1H,dd), 4.27(1H,m),4.54(1H,dd), 4.61 (1H,dd), 6.02(1H,d), 7.98(1H,s)

2-iodo-3'-O-methyladenosine (Compound 48)

¹ H-NMR (D₂ O): 3.58(3H,s) 3.86(1H,dd) 3.94(1H,dd), 4.18(1H,dd)4.35(1H,m) 4.97(1H,dd) 5.93(1H,d), 7.94(1H,s)

In the same manner the following compounds were obtained by using2-substitutedadenosine, N⁶ -substitutedadenosine or 2, N⁶-disubstitutedadenosine.

2-Methoxy-3'-O-methyladenosine (Compound 9)

¹ H-NMR (D₂ O): 3.56(3H,s) 3.84(1H,dd), 3.94(1H,dd), 3.96(3H,s)4.22(1H,dd) 4.33(1H,m) 5.06(1H,dd), 5.98(1H,d) 8.10(1H,s,8-H)

N⁶,2'-O-Dimethyl-2-hexyladenosine (Compound 30)

¹ H-NMR (MeOH-d₄): 0.88(3H,t) 1.33(6H,m), 1.78(2H,quintet), 2.74(2H,t),3.12(3H,brs), 3.37(3H,s), 3.73(1H,dd), 3.88(1H,dd), 4.18(1H,m),4.49(2H,m), 5.98(1H,d), 8.10(1H,s,8-H)

N⁶,2'-O-Dimethyl-2-decyladenosine (Compound 31)

¹ H-NMR (MeOH-d₄): 0.88(3H,t), 1.27-1.33(14H,m), 1.78(2H,quintet),2.75(2H,t), 3.13(3H,brs), 3.37(3H,s), 3.73(1H,dd), 3.89(1H,dd),4.18(1H,m), 4.49(2H,m)

N⁶,2'-O-Dimethyl-2-(1-hexyn-1-yl)adenosine (Compound 32)

¹ H-NMR (MeOH-d₄): 0.97(3H,t), 1.52(2H,m), 1.62(2H,m), 2.54(2H,t),3.09(3H,brs), 3.40(3H,s), 3.74(1H,dd), 3.88(1H,dd), 4.15(1H,m),4.42(1H,dd), 4.48(1H,dd), 6.00(1H,d), 8.22(1H,s)

N⁶,2'-O-Dimethyl-2-(1-dodecyl-1-yl)adenosine (Compound 33)

¹ H-NMR (MeOH-d₄): 0.89(3H,t), 1.30(14H,m), 1.49(2H,m),1.63(2H,quintet), 2.43(2H,t), 3.41(3H,s), 3.74(1H,dd), 3.88(1H,dd),4.15(1H,m), 4.41(1H,dd), 4.48(1H,dd), 6.00(1H,d), 8.30(1H,s)

2-Phenyl-2'-O-methyladenosine (Compound 37)

¹ H-NMR (MeOH-d₄): 3.53(3H,s), 3.77(1H,dd), 3.91(1H,dd), 4.12(1H,m),4.50(1H,dd), 4.54(1H,dd), 6.20(1H,d), 7.43(3H,m), 8.32(2H,m), 8.36(1H,s)

2-Phenyl-3'-O-methyladenosine (Compound 38)

¹ H-NMR (MeOH-d₄): 3.53(3H,s), 3.74(1H,dd), 3.88(1H,dd), 4.10(1H,dd),4.22(1H,m), 5.00(1H,dd), 6.07(1H,d), 7.42(3H,m), 8.32(3H,m)

2-Bromo-2'-O-methyladenosine (Compound 43)

¹ H-NMR (D₂ O): 3.50(3H,s), 3.91(1H,dd), 3.99(1H,dd), 4.37(1H,m),4.57(1H,dd), 4.67(1H,dd), 6.13(1H,d), 8.37(1H,s)

2-Bromo-3'-O-methyladenosine (Compound 44)

¹ H-NMR (D₂ O): 3.60(3H,s), 3.90(1H,dd), 4.01(1H,dd), 4.19(1H,dd),4.44(1H,m), 4.95(1H,dd), 6.07(1H,d), 8.37(1H,s)

2-Bromo-N⁶,2'-O-dimethyladenosine (Compound 45)

¹ H-NMR (D₂ O): 3.22(3H,s), 3.57(3H,s), 3.90(1H,dd), 3.98(1H,dd),4.29(1H,m), 4.59(1H,dd), 4.65(1H,dd), 6.12(1H,d), 8.16(1H,s)

2-Bromo-N⁶,3'-O-dimethyladenosine (Compound 46)

¹ H-NMR (D₂ O): 3.07(3H,s), 3.60(3H,s), 3.93(1H,dd), 3.99(1H,dd),4.23(1H,dd), 4.36(1H,m), 5.03(1H,dd), 6.03(1H,d), 8.14(1H,s)

2-Pentylamino-2'-O-methyladenosine (Compound 52)

¹ H-NMR (MeOH-d₄): 0.94(3H,t), 1.38(4H,m), 1.65(2H,m), 3.42(2H,t),3.49(3H,s), 3.76(1H,dd), 3.87(1H,dd), 4.08(1H,m), 4.25(1H,t),4.43(1H,t), 5.99(1H,d), 8.22(1H,s)

2-Phenylamino-2'-O-methyladenosine (Compound 53)

¹ H-NMR (MeOH-d₄): 3.46(3H,s), 3.74(1H,dd), 3.85(1H,dd), 4.07(1H,m),4.23(1H,dd), 4.39(1H,dd), 6.03(1H,d), 7.11(1H,t), 7.35(2H,t),7.60(2H,d), 8.35(1H,s)

2-Phenylamino-3'-O-methyladenosine (Compound 54)

¹ H-NMR (MeOH-d₄): 3.46(3H,s), 3.69(1H,dd), 3.79(1H,dd), 3.94(1H,dd),4.16(1H,m), 4.74(1H,dd), 5.91(1H,d), 7.13(1H,t), 7.36(2H,t), 7.60(2H,d),8.28(1H,s)

2-Phenylamino-N⁶,2'-O-dimethyladenosine (Compound 55)

¹ H-NMR (MeOH-d₄): 3.16(3H,s), 3.47(3H,s), 3.77(1H,dd), 3.88(1H,dd),4.11(1H,m), 4.20(1H,dd), 4.40(1H,dd), 6.06(1H,d), 7.12(1H,t),7.35(2H,t), 7.63(2H,d), 8.42(1H,s)

2-Phenylamino-N⁶,3'-O-dimethyladenosine (Compound 56)

¹ H-NMR (MeOH-d₄): 3.10(3H,s), 3.49(3H,s), 3.72(1H,dd), 3.85(1H,dd),3.98(1H,dd), 4.17(1H,m), 4.85(1H,dd), 5.88(1H,d), 6.94(1H,t),7.26(2H,t), 7.69(2H,d), 7.99(1H,s)

2-(3-Hydroxy-1-propyn-1-yl)-2'-O-methyladenosine (Compound 57)

¹ H-NMR (D₂ O): 3.45(3H,s), 3.86(1H,dd), 3.95(1H,dd), 4.32(1H,m), 4.51(1H,dd), 4.52(2H,s), 4.62(1H,dd), 6.08(1H,d), 8.30(1H,s)

2-(3-Hydroxy-1-propyn-1-yl)-3'-O-methyladenosine (Compound 58)

¹ H-NMR (D₂ O+MeOH-d₄): 3.51(3H,s), 3.80(1H,dd), 3.92(1H,dd),4.09(1H,m), 4.36(1H,m), 4.47(2H,s), 4.83(1H,dd), 5.96(1H,d), 8.30(1H,s)

EXAMPLE 8

2.2 g of AICA-2'-O-methylriboside was dissolved in 20 ml ofdimethylformamide and 1.7 g of benzoylisothiocyanate was added thereto.After stirring for 3 hours at room temperature, 3.3 g ofdicyclohexylcarbodiimide was added and reacted for 20 hours at roomtemperature. The reaction mixture was concentrated to an oily residue.To the residue, 50 ml of ethanol and 50 ml of aqua ammonia were added,and stirred for 18 hours at room temperature.

The resulting precipitate was collected by filtration to give 1.7 g of2-hydroxy-2'-O-methyladenosine (Compound 39).

¹ H-NMR (D₂ O): 3.46(3H,s), 3.82(1H,dd), 3.90(1H,dd), 4.27(1H,m),4.50(1H,dd), 4.59(1H,dd), 5.95(1H,d), 8.03(1H,s)

In the same manner, AICA-3'-O-methylriboside was used as a startingmaterial to give 2-hydroxy-3'-O-methyladenosine (Compound 40).

¹ H-NMR (D₂ O): 3.54(3H,s), 3.82(1H,dd), 3.94(1H,dd), 4.10(1H,dd),4.36(1H,m), 4.86(1H,dd), 5.89(1H,dd), 8.03(1H,s)

The following descriptions serve to illustrate pharmaceutical studies ofthe compounds of the present invention.

1. Adenosine Deaminase Inhibiting Action

The enzymatic reaction was conducted at 25° C. in a 0.05M phosphatebuffer (pH=7.5). Thus, a reaction solution comprising 800 μl ofsubstrate solution (adenosine), 100 μl of a solution to be tested and100 μl of enzyme solution (adenosine deaminase of type VII; mucousmembrane of intestinal tract of calf) was reacted for 5 minutes and thereaction was stopped by adding 100 μl of acetic acid. Then the amount ofinosine produced was determined by means of an HPLC to measure theinhibiting activity. The test was conducted for various substrateconcentrations and Ki values were measured by Lineweaver-Burk plots.

Examples of the results are given in Table 1.

                  TABLE 1                                                         ______________________________________                                        Compound      Ki Value                                                        Tested        (M)                                                             ______________________________________                                         1            1.31 × 10.sup.-5                                           2            4.93 × 10.sup.-4                                           4            3.47 × 10.sup.-6                                           5            2.46 × 10.sup.-5                                           6            1.79 × 10.sup.-4                                          18            1.24 × 10.sup.-6                                          19            7.78 × 10.sup.-5                                          20            2.69 × 10.sup.-4                                          21            3.30 × 10.sup.-7                                          22            5.58 × 10.sup.-8                                          23            8.90 × 10.sup.-7                                          24            1.10 × 10.sup.-7                                          25            3.59 × 10.sup.-4                                          27            8.59 × 10.sup.-7                                          30            9.00 × 10.sup.-8                                          31            2.80 × 10.sup.-7                                          32            1.20 × 10.sup.-7                                          33            1.50 × 10.sup.-5                                          34            3.59 × 10.sup.-4                                          37            6.60 × 10.sup.-7                                          38            7.90 × 10.sup.-6                                          39            1.90 × 10.sup.-5                                          43            3.20 × 10.sup.-6                                          44            2.20 × 10.sup.-5                                          45            1.20 × 10.sup.-7                                          46            3.70 × 10.sup.-6                                          47            2.30 × 10.sup.-7                                          48            4.40 × 10.sup.-6                                          50            2.80 × 10.sup.-5                                          51            5.00 × 10.sup.-6                                          52            6.00 × 10.sup.-7                                          53            1.70 × 10.sup.-7                                          54            2.20 × 10.sup.-6                                          55            1.30 × 10.sup.-8                                          56            1.10 × 10.sup.-7                                          57            3.00 × 10.sup.-5                                          59            7.50 × 10.sup.-6                                          60            7.50 × 10.sup.-7                                          61            1.50 × 10.sup.-7                                          63            1.30 × 10.sup.-6                                          64            8.80 × 10.sup.-7                                          73            1.03 × 10.sup.-3                                          ______________________________________                                    

2. Therapeutic Action to Nephritis.

When puromycin aminonucleoside is administered to rats, symptoms similarto protein-rich urine, hypoproteinemia, hyperlipemia, nephroticsyndrome, etc, result and, therefore, rats which are administered withpuromycin aminonucleoside have been used as pathological model animalsfor nephritis. The chemical name for puromycin aminonucleoside is3'-amino-3'-deoxy-N,N-dimethyladenosine. A method by Endo, et al. SogoRinsho, vol. 38, no. 5, page 821 (1989)! was somewhat modified and usedas a test method here. Thus, a solution of puromycin aminonucleoside wasdissolved in a physiological saline liquid and administered just once toa tail vein of a male rat (SD strain) of about 200 g body weight at adose of 100 mg/kg (the initial of zero-th day).

The compound to be tested was dissolved in a physiological saline liquidand was given orally for five consecutive days from the zero-th day at adose of 50 mg/kg each. After 24 hours, the accumulated urine wascollected and the amount of urine and the amount of protein in the urinewas measured. Blood was collected on the tenth day and the total proteinin serum, creatinine in serum and urea nitrogen were measured.

Examples of the results are given in Tables 2 and where the control isthose animals injected only with the puromycin aminonucleoside:

                  TABLE 2                                                         ______________________________________                                                                Total Protein                                                                           Serum                                       Compound to be                                                                            Urea Nitrogen                                                                             in Serum  Creatinine                                  Tested      (mg/dl)     (g/dl)    (mg/dl)                                     ______________________________________                                        Normal      17.6        7.90      0.38                                        Control     40.0        7.08      0.85                                        Compound 27 31.9        7.44      0.71                                        ______________________________________                                    

                  TABLE 3                                                         ______________________________________                                                    Amount of Protein in Urine                                                    (mg/day)                                                          Days          Control Compound 27                                             ______________________________________                                        1st Day       0       0                                                       2nd           32.0    29.2                                                    3rd           44.7    33.8                                                    4th           173.4   122.5                                                   5th           522.5   399.8                                                   6th           704.1   443.7                                                   7th           826.5   558.7                                                   8th           811.6   595.6                                                   9th           814.0   593.5                                                   10th          684.0   528.6                                                   ______________________________________                                    

3. Inhibitory Action against Activated Oxygen Generation

Human peripheral polymorphonuclear leukocyte (PML, 2×10⁶ cells) preparedin a conventional method, bovine heart cytochrome C type-III (75 nmol),cytocharasin (5 μg) and tested drug were mixed with HEPES-bufferedsaline solution (final 1 ml) and incubated for 5 minutes at 37° C.N-Formyl-methionyl-leucyl-phenylalanine (FMLP) was added (final 10⁻⁷ M)and incubated for 5 minutes. Immediately after the incubation, thereaction mixture was centrifuged at 4° C., and then the absorbance at550 nm of the supernatant was measured with a spectrophotometer.

An excess amount of bovine liver superoxide dismutase (SOD) was added tothe reaction mixture and the absorbance of the supernatant was alsomeasured in the same manner as above as a blank value.

A portion of adenosine deaminase (ADA) may be removed during thepreparation of human peripheral PML. Therefore, the inhibitory actionagainst the generation of superoxide of the tested drug was measured inthe same manner as mentioned above, adding 0.02 units of bovine liverADA with human peripheral PML.

The inhibition against superoxide generation was calculated by thefollowing equation, and examples of the results are given in Table 4.##EQU1##

                  TABLE 4                                                         ______________________________________                                        Without ADA           With ADA                                                Compound 27 (M)                                                                          Inhibition Compound 27 (M)                                                                            Inhibition                                 ______________________________________                                        1 × 10.sup.-3                                                                      100%       1 × 10.sup.-4                                                                        88%                                        1 × 10.sup.-4                                                                      79%        1 × 10.sup.-5                                                                        77%                                        1 × 10.sup.-5                                                                      22%        1 × 10.sup.-6                                                                        34%                                        1 × 10.sup.-6                                                                       2%        1 × 10.sup.-7                                                                        10%                                        ______________________________________                                         4. Suppressive Action against Ischemic Edema                              

The right hind paw of ICR-strain male mice (11 weeks of age) werefastened with a rubber band to stop the blood stream for 20 minutes, andthen the rubber band was removed to recover the blood stream. The testeddrug was administered intravenously before the treatment. Each of theright and left hind paws were weighed and the suppressive action wasmeasured according to the weight difference between the treated anduntreated paws.

Examples of the results are given in Table 5.

                  TABLE 5                                                         ______________________________________                                        Tested Drug Paw Weight (mg)  Inhibition                                       (10 mg/kg) Treated     Untreated (%)                                          ______________________________________                                        Control    314.8 ± 6.8                                                                            219.9 ± 6.2                                                                          --                                           Compound 27                                                                              254.4 ± 6.6                                                                            223.86.2  67.7                                         Allopurinol                                                                              283.2 ± 6.3                                                                            222.9 ± 6.9                                                                          36.4                                         ______________________________________                                    

5. Effect on the Concentrations of Adenosine and Inosine

Human peripheral polymorphonuclear leukocyte (2×10⁶ cells), cytochalasin(5 μg) and the tested drug were mixed with HEPES-buffered salinesolution (final 0.5 ml) and incubated for 5 minutes. FMLP was added(final 10⁻⁷ M) and incubated for 10 minutes. As a result of HPLCanalyses of the reaction mixture, in FMLP-treated group, the inosinepeak increased compared to the control group. The compound of thepresent invention was added to the FMLP-treated group, which showed adecrease in the inosine peak and a significant increase in the adenosinepeak compared with the group when the compound of the present inventionwas not added.

As shown in Table 1, the compounds of the present invention exhibitexcellent adenosine deaminase inhibiting action. Adenosine deaminasewhich is a metabolic enzyme for adenosine is inhibited whereby theadenosine concentration in tissues increases. Neutrophils produceactivated oxygen when the tissue is in an ischemic state. Adenosineinhibits the production of activated oxygen and, in addition, adenosinedirectly eliminates the produced activated oxygen. Further, adenosinelowers the inosine concentration whereby it decreases the supply ofhypoxanthine. Hypoxanthine is a substrate of xanthine-xanthineoxidasesystem. The xanthine-xanthineoxidase system is one of the systemsproducing the activated oxygen. Adenosine deaminase inhibiting substancehaving a production inhibiting action and an eliminating action foractivated oxygen source as such shows pharmacological actions such asimprovement of coronary and cerebral blood vessel circulation,prevention and therapy of renal diseases, antiinflammatory activity,etc.

Further, as shown in Tables 2 and 3, the compounds of the presentinvention having adenosine deaminase inhibiting action were evaluated bymeans of pharmacological experiments. Rats which had been administeredwith puromycin aminonucleoside were used as pathological model animalsfor nephritis. Indexes such as total protein in serum, creatinine inserum and urea nitrogen concentrations were used to evaluate thetherapeutic effects of the instant compounds.

Consequently, the compounds of the present invention having adenosinedeaminase inhibiting action are useful as pharmaceuticals for theprevention and therapy of various kinds of diseases such as ischemicheart diseases, diseases caused by cerebrovascular disorder, renaldiseases, and allergic diseases. Examples of ischemic heart diseaseswhich may be treated include angina pectoris, myocardial infarction andarrhythmia. Exemplary of diseases caused by cerebrovascular disorderwhich may be treated are cerebral hemorrhage, cerebral infarction,cerebral apoplexy and cerebral arteriosclerosis. Nephritis and renalfailure are examples of renal diseases which may be treated and examplesof allergic diseases which may be treated include asthma, allergicrhinitis, allergic conjunctivitis, urticaris and rheumatism. Moreover,the compounds of the present invention are very useful aspharmaceuticals for the prevention and therapy of post-operativecomplicated diseases because they inactivate activated oxygen which isgenerated in ischemic areas during the recirculation of blood afteroperations.

Adenosine analogs such as 3'-deoxyadenosine and xylosyladenine(anticancer drugs) and arabinosyladenine (exhibiting antiherpesactivity) are easily deaminated by adenosine deaminase in vivo and areinactivated. Accordingly, when the compounds of the present inventionhaving adenosine deaminase inhibiting action are administered before ortogether with administration of the above-mentioned anticancer drugs orantiviral drugs, an effect of inhibiting the decrease in action of suchadenosine analogous anticancer and antiviral drugs can be expected aswell. For the purposes of this invention, an adenosine analogous drug isdefined as a drug which is metabolized or deaminated by adenosinedeaminase.

Adenosine has many pharmacological activities such as cardiovasodilatingor platelet-aggregation inhibiting activity, so adenosine is used toimprove blood circulation and treat heart failure, myocardial infarctionand other such conditions. Adenosine is metabolized by adenosinedeaminase and is consequently inactive. Accordingly, when the compoundsof the present invention are administered before or together with theadministration of adenosine, the instant compounds may inhibit thedecrease in such action of adenosine.

The compounds of the present invention can be made into pharmaceuticalsby combining them with suitable carriers or diluents. The compounds ofthe present invention can also be made into pharmaceutical preparationsby any of the conventional methods giving solid, semisolid, liquid orgaseous forms for oral or parenteral administration.

In manufacturing such preparations, the compounds of the presentinvention may be used in the form of their pharmaceutically acceptablesalts. The compounds of the present invention may be used either solelyor jointly in the form of a suitable combination. Alternatively, thecompounds may be compounded with other pharmaceutically activecomponents.

In the case of oral preparations, the compounds of the present inventionmay be used alone or combined with appropriate additives to maketablets, diluted powders, granules or capsules. The compounds may becombined with conventional fillers such as lactose, mannitol, cornstarch, and potato starch; binders such as crystalline cellulose,cellulose derivatives, gum arabic, corn starch and gelatin; lubricantssuch as talc and magnesium stearate; disintegrators such as corn starch,potato starch or sodium carboxymethylcellulose; and if desired withdiluents, buffering agents, extenders, moisturizers, preservatives,flavoring agents and perfumes.

Alternatively, the compounds of the present invention may be made into asuppository by mixing with a variety of bases. Exemplary bases includefatty and oil bases such as cocoa butter, emulsifying bases,water-soluble bases such as Macrogol and hydrophilic bases.

In the case of injections, the compounds may be dissolved, suspended oremulsified in aqueous solvents or nonaqueous solvents. Examples ofaqueous and nonaqueous solvents include distilled water, physiologicalsaline liquid, Ringer solution and solutions containing plant oil,synthetic fatty acid glycerides, vegetable oil, higher fatty acid estersand propylene glycol.

Further, depending upon the state of the patient, or the type of thedisease, the compounds may be made into other preparation forms whichare most suitable for the therapy such as inhalants, aerosols,ointments, poultices and eye drops. In the case of inhalations oraerosol preparations, the compounds of the invention in the form of aliquid or a minute powder can be filled up in an aerosol container withgas or a liquid spraying agent, and if desired, with conventionaladjuvants such as humidifying agents or dispersing agents.

Cataplasms can be prepared by mixing the compounds with mentha oil,concentrated glycerin, kaolin or other such additives.

The desired doses of the compounds of the present invention varydepending upon the patient to be treated, the preparation form, themethod of administration, and the period of administration. In general,0.1 to 5,000 mg or, preferably, 0.2 to 3,000 mg per day may be given toan adult by oral route for achieving the desired effect.

In the case of parenteral administrations such as injections, doses ofthe compounds on the order of one third to one tenth of the above doseare preferable as daily doses.

It is claimed:
 1. An adenosine derivative represented by the followingformula or a pharmaceutically acceptable salt thereof: ##STR13## whereineach of R₁ a, R₂ a and Xa may be the same or different and is hydrogenor alkyl, at least one of R₁ a and R₂ a being an alkyl; andRa is analkyl having more than 6 carbons, alkenyl, alkynyl, hydroxyalkynyl,alkoxy, phenyl, hydroxy, alkylamino or phenylamino.
 2. An adenosinederivative represented by the following formula or a pharmaceuticallyacceptable salt thereof: ##STR14## wherein R₁ b and R₂ b are the sameand each is methyl or ethyl; Rb and Xb is hydrogen or methyl; andatleast one of Rb and Xb is methyl.
 3. An adenosine derivative representedby the following formula or a pharmaceutically acceptable salt thereof:##STR15## wherein one of R₁ c and R₂ c is methyl and the other ishydrogen;when Xc is hydrogen, Rc is iodo; and when Xc is methyl, Rc isbromo or iodo.
 4. An adenosine derivative represented by the followingformula or a pharmaceutically acceptable salt thereof: ##STR16## whereinR₁ d is an alkyl having 2 to 8 carbons.
 5. An adenosine derivative asclaimed in claim 1 wherein R₁ a is alkyl.
 6. An adenosine derivative asclaimed in claim 3 wherein R₁ c is methyl.
 7. A pharmaceuticalcomposition comprising:(a) at least one adenosine deaminase inhibitorcomprising at least one of the compounds represented by the formula (I)or a pharmaceutically effective salt thereof: ##STR17## wherein each ofR₁, R₂ and R₃ may be the same or different and R₁, R₂ and R₃ is hydrogenor alkyl, at least one of R₁, R₂ and R₃ being an alkyl; R is hydrogen,alkyl, alkenyl, alkynyl, hydroxyalkynyl, alkoxy, phenyl, hydroxy, amino,alkylamino, phenylamino or halogen; and X is hydrogen, alkyl, alkynyl,allyl, methallyl, cycloalkyl, an alkyl having one or more hydroxygroups, phenyl, substituted phenyl, alkyl having one or more phenylgroups, alkyl having one or more substituted phenyl groups,bicycloalkyl, naphthalkyl, acenaphthylenylalkyl or a group representedby Formula (II) or Formula (III): ##STR18## wherein Z is hydrogen,hydroxy or lower alkoxy; Q is hydrogen or hydroxy; A is --CH₂ --, --O--,--S-- or a single bond forming a five-membered ring; Y is --(CH₂)_(n) --or a single bond; n is an integer from 1 to 3; and (b) adenosine or atleast one therapeutically useful adenosine analogous drug which isdifferent from (a) and which is metabolized or deaminated by adenosinedeaminase; as active ingredients wherein said adenosinedeaminaseinhibitor inhibits loss of activity of said adenosine or said adenosineanalogous drug.
 8. The composition of claim 7 wherein said adenosineanalogous drug is an anticancer drug, or an antiviral drug, or acombination of an anticancer drug with an antiviral drug.
 9. Thecomposition of claim 8 wherein said anticancer drug is 3'-deoxyadenosineor xylosyladenine and said antiviral drug is arabinosyladenine.
 10. Thecomposition of claim 7 wherein R₃ is hydrogen.
 11. The composition ofclaim 10 wherein X is hydrogen.
 12. The composition of claim 10 whereinX is an alkyl having 1 to 3 carbon atoms.
 13. The composition of claim 7wherein R₁ is an alkyl.